I. Field of the Invention
The present invention relates to a transfected human amniotic cell and to a method for treating hereditary diseases using the same.
II. Description of the Related Art
Main conventional methods for gene therapy in which a foreign gene is introduced into a patient so as to treat a hereditary disease include a method utilizing cells as a drug delivery system (DDS). An example of gene therapy of this type is a method for treating a hereditary disease such as adenosine deaminase deficiency or purine nucleotide phosphorylase deficiency, in which the gene of such an enzyme is inserted into a retrovirus vector, bone marrow cells collected from a patient are transfected with the recombinant vector, and the transfected bone marrow cells are autogenously transplanted to the patient. With this method, since bone marrow cells of the patient are used and the transfected cells must be transplanted into the bone marrow, the damage to the patient is large. It is also known to introduce a foreign gene into lymphocytes of the patient and to give the lymphocytes back to the patient. However, with this method, the therapy must be repeatedly performed and hereditary diseases which can be cured by this method are limited.
On the other hand, since amniotic cells do not express HLA-A, B, C and DR antigens as well as .beta..sub.2 -microglobulin, and produce large amounts of lysosomal enzymes, the possibility to treat lysosomal storage diseases which are hereditary diseases using amniotic cells has been suggested (Adinolfi, M. et al., Nature 295:325-327, 1982). Thus, it is known to use amniotic cells as a DDS in therapies of hereditary diseases. Transplantation of amniotic tissue has been carried out for treating inborn errors of metabolism such as mucopolysaccharidosis and lipidosis, and the effectiveness of the therapies for a part of the patients has been confirmed (Tylki-Szymanska A et al., J. Inher Metab Dis 8:101-104, 1985; Sakuragawa N et al., Brain & Dev 14:7-11, 1992). Clinically, rejection reactions in these patients have not been reported. However, this technique utilizes the amniotic cells as a DDS of an enzyme which is intrinsically produced by the amniotic cells. It has not been suggested to introduce a foreign gene into amniotic cells, and actually transfected amniotic cells have not been reported. In addition, immunogenecity of the amniotic cells has not been studied in detail after the above-mentioned report.